1. Field of the Invention
The present invention is in the field of binding and baling operations, more particularly in the field of wire knotting.
2. Related Art
In the field of binding and baling bulk material items such as cotton with wire, a variety of mechanical wire knotters are known in the art. These knotters work in conjunction with a baling equipment bed through a variety of techniques wraps a length of wire around a volume of bulk material to be baled and delivers a leading end of each individual wire proximate to a trailing end, the same wire, which has been cut by the baling machine. These wire ends are then acted upon by wire knotters to secure them so that they will retain the bulk material bale in a compressed volume after the baling machine releases the bale.
Knotting is typically achieved by twisting the two wire ends around one another. To do so, the wire ends are captured together in a slot or groove and then a gear wheel pinion or the like rotates in order to twist them together. After the twisting operation is complete, the separate mechanical component pushes the knotted wires out of the groove because the overall knotting apparatus is generally configured around a rotating drive shaft which delivers a rotational energy through a series of gears to the actual knotting linkage, it is advantageous for the ejector mechanism to also be actuated by a rotational device.
Hence in the prior art, ejector drive hubs were designed. These hubs had capacity to be driven by the overall drive shaft, typically by a boss detent. They also had a capacity to be held stationary while the drive shaft and other machinery rotated during knotting, typically by a latch and notch arrangement. Finally, the ejector drive had an extension boss or the like mentioned in position to engage corresponding boss or extension on an ejector in order to first drive it for ejection of the wire and secondly return the ejector to its rest position.
Baling is often of bulk materials comprised of agricultural products and is hence a seasonal activity. Accordingly, speed is of the essence in order to process large volumes of bulk material in a short amount of time. Therefore the balers and knotters are designed to work very quickly have a high throughput and perform a large number of cycles in succession. Additionally, bales are typically bound under tons of pressure and the wires to be knotted are required to meet standards wiring the knots to remain bound under thousands of pounds of tension. These high tensions can put extra strain on knotter parts.
Prior art ejector drive hubs, the actual drive boss designed to engage the ejector to actuate it was a separate piece to be attached to the rotating disc portion of the ejector drive hub. Attachment can be by a variety of methods, such as threading the boss and screwing it into a corresponding hole and the disc, bolting or otherwise. However, due to the high stress, high turnover and rapid cycle time necessary for mechanical knotter operations, such two-part construction of ejector drive hubs lead to frequent breakage due to wear of the fixation between the boss and disc. Finally, a cam is required to operate prior art ejector drive hubs.
There is a need in the art for greater durability of ejector drive hubs for wire knotters. Moreover, there remains a continuing need for ease of manufacture of ejector drive hubs, reduction of extraneous parts and economy. Durability of the properly positioned boss relative to the disc portion of the ejector drive hub is related to the continuing need for a maintenance precise positioning of the boss over many cycles in order that its engagement with the other moving parts of the knotter made efficient.
Finally, through many cycles of use, wear deforms or erodes inter-operative faces on the ejector and ejector drive hub, causing parts to vary from designed tolerances. There is a need for a boss design or shape that continues to operate well during and after wear of the parts.